Set Default Font ..and Font-Size

hi All I am searching for a way to set the font-size of the text editor to a fixed 12 and the font to fixed time new roman..I do not want to allow my users to changes those two settings in particular can anyone guide me how to do that

You can change the styles for the editorArea by changing the CSS for the body in the file 'editor/css/fck_editorarea.css'. If you don't see any changes, delete or disable your cache. Then edit your toolbarset to disbale any of the controls you don't want to offer to your users.